Method of positioning magnetically responsive sleeves within a mass of moldable material



Och 2- w. E. s. STRONG ETAL 2,297,923

METHOD OF POSITIONING M ETICAL RESPONS SLEEVES WITHIN MASS MOLDABMATERIA Filed July 11, 1939 INVENTOR WILLIAM E.5.5TRO AND CHARLES E ARw? l 1 THEN: ORNEY Patented Oct. 6, 1942 METHOD OF POSITIONINGMAGNETICAILY RESPONSIVE SLEEVES WITHIN A MASS OF LIOLDABLE MATERIALWilliam E. S. Strong, New York, N. Y., and Charles E. Parsons,Princeton, N. J., assignors to John B. Pierce Foundation, New York, N.Y., a corporation of New York Application July 11, 1939, Serial No.283,724

3 Claims.

This invention relates to anchorage devices and-to methods ofpositioning the same.

More particularly. this invention relates to an improved method forpro-positioning sockets or liners adapted for employment with structuresformed from concrete or other moldable, hardsetting material, to formanchorage means for male-threaded elements.

The present invention contemplates the use of .a magnetic metallic shellwall insert having an open end. The wall structure of such insert isformed with deep-shouldered threading, whereby upon pouring concreteabout the insert, a portion of said concrete fills the lower portion ofthe insert and supplements the engagement of the concrete with theexternal threading, to secure the insert against withdrawalorsubstantial separation from the hardened concrete or like material.

By the employment of magnetic materials for the anchorage device, meansare afforded whereby said anchorage devices may be magnetically held 1on a suitable jig or other supporting means during the stage of pouringthe concrete or like material, and the holding devices readily removedtherefrom after the concrete has hardened.

It is a feature of the invention that the holdin power of, the insert isderived by means other than a distortion ofthe walls thereof, outwardexpansion against the walls of a drilled openin within the holdingstructure, or by external wings, ilns, or the like. Itis an additionalfeature that the lag screw may be removed and re-inserted, withoutdamaging the sleeve or adversely affecting its holding power.

This application is a continuation in part of our presently copendingapplication Serial No. 156,699,1l1ed July 31, 1937, entitled Anchoragedevice.

Other features and advantages will hereinafter appear.

In the accompanying drawing:

Figure'l is an elevation, partly in section, of a screw-threaded linerpursuant to the present invention;

Figure 2 illustrates a preferred method of positioning the liner andholding the same during the molding of the concrete mass;

Figure 3 is illustrative of the application of the liner and theengagement of concrete with the internal and external threading thereof;

Figure 4 is a plan view of the liner.

The anchoring device or liner 10, Fig. 1, comprises a helicallyconflgurated, open ended cylinder, preferably of steel, sheet iron, orlike sheet metal, advantageously formed by die-embossing thread-formingcorrugations on a flat metal blank, and shaping said blank around amandrel to form a cylinder, the extremities of the corrugations beingbrought into register to form a continuous thread.

It will be understood that materials other than steel or sheet iron maybe used for manufacturing our anchoring devices; magnetic materials,however, lend themselves advantageously to desirable means ofpositioning and holding the liners during the pouring and compacting ofthe cementitious mass, as later described.

As illustrated in Figure l, the liner Ill has a deep shouldered femalethreading I1, and a male thread provided with sloping,collapse-resistant shoulders or abutments l8. l'he liner mayadvantageously be used with any moldabie material which, althoughpossessing desirable structural qualities in mass, is of a friablenature in that corner-surfaces or threadlike configurations crumbleunder abrasion combined with tensile or compressive stresses, suchfriable characteristic making it impracticable to tan or otherwise forma screw-thread in the material per se.

Fig. 2 illustrates a preferred method of positioning a liner oranchorage device In during the stage of pouring and compacting a cementslab 20. A liner l0 may be inserted over a mandrel 22 of soft iron orlike magnetic material, said mandrel forming the core of anelectromagnetic holding device 23 connected, as shown, to any suitablesource of electric current.

Any suitable switch means, as 2%, may be provided in the circuit.

When it is desired to position a plurality of anchorages H3 in oneoperation, a suitable ji having such plurality of electromagneticdevices 23 may be employed, each of the cores 22 of which receive ananchorage l0.

Closing the switch 24 nergizes the electroma net 23, retaining theanchorage It! for suitable positioning with respect to a mold, one wall,2 I, of which is shown.

As appears in Fig. 2, the core 22 is shorter than the anchorage devicein, to maintain a substantial portion of the end of the anchorage inopen status.

' The cementitious mass may then be introduced into the mold, whereuponit flows into engage- I ment with the shoulders 18 of the external wallshoulders of the internal corrugation ll. Desirably, the concrete massis jarred or compacted to densify the mass and to insure the intimateengagement of the concrete with the corrugations of the anchorage devicel0.

Upon the opening of the electric circuit the electromagnetic holdingmeans 22, 23 may be removed. I

As is shown in Fig. 3, the anchorage lli is secured within the cementslab 20 by the engagement of hardened concrete with the externalshoulders l8, and by the coincident engagement of a concrete slug 20a,integral with the main body 20, with several of thelowermost internalcorrugations H. The anchorage device is, therefore, characterized by theabsence of external projections; the maximum external diameter of theanchorage device being only slightly greater than the maximum externaldiameter of the la screw 25, said device is adaptable for use inrestricted locations. It is thus possible to position said devices incomers or like locations where the proximity of a plurality of wallsurfaces may preclude the use of anchorages having wing-like The metalof the liner is substantially unmutilated by the lag screw 25, and,therefore, the

. stated screw can be removed and re-inserted without damaging the lineror detracting from its holding power.

Desirably, the length of the anchorage device or liner in afifords fullthreaded engagement with the threads of the lag screw or the like, andadditionally provides alength of engagement of the concrete with theinternal threading ll of the order of one-quarter of the total threadedlength of the liner.

It will be observed that the sleeve W is not held within the slab 20 byexpansion or other pressure-induced distortion. The sloping shoulders l8resist tensile pull on the sleeve it along frusto-conical surfacesestablished within the mass, and normal to the said shoulders, asindicated by the arrowed lines in Fig. 3.

The liner l0 may be provided with a. suitable rust-resistant coating,such as tin or zinc. The close bond between the concrete of the slab 20and the liner I0 precludes the penetration of water around the liner,and plastic cement may be utilized to seal the space between the shankof the lag screw and the inner wall of the liner to prevent thepercolation of water therein.

Whereas a specific form of our invention has been described, it will beunderstood that many changes and modifications may be made withoutdeparting from the spirit of the invention.

We claim:

1. The method of securing a screw anchor having an open end and ascrew-thread provided internal and external wall within a, mass ofhardsetting moldable material, comprising inserting an electromagneticcore into said anchor to plug all but the lower portion thereof againstthe entry of said moldable material, energizing said electromagneticcore to retain said anchor thereon, causing said hard-setting moldablematerial to flow about the externalwall of said anchor and to flow intothe said open end of said anchor to engage the screw-threadingthereof,-de-energizing said electromagnetic core after said moldablematerial has set, and removing 'said core therefrom.

2. The method of positioning an open-ended sleeve within a mass ofhard-setting moldable material, comprising magnetically retaining saidsleeve on a core disposed internally thereof, inserting the thus mountedand magnetically held sleeve into a mass of such material, whereby saidmaterial enters the open end of said sleeve to an 'extent permitted bysaid core, and withdrawing said core from said sleeve after the saidmoldable material has rigidified suficiently to preclude anyfurther-substantial entry of said material into said open-ended sleeve.

3. The methodof positioning a magnetically responsive open ended tubularsleeve within a mass of hard-setting moldable material, comprising thesteps of plugging said sleeve over all but a desired portion of itslength, magnetically holding such plugged-sleeve in desired position,causing said mass of moldable material to flow about said sleeve andinto the open end thereof, permitting said moldable material tosolidify, and releasing said magnetic holding means and removing'theplug means from said sleeve.

WILLIAM E. s. STRONG.- CHARLES E. PARSONS.

